package com.jxtti.interceptor;
/**
 * java类过滤器，防止页面sql注入
 */
import java.io.IOException;
import java.util.Enumeration;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;

public class AntiSqlInjectionfilter implements Filter {

	public void destroy() {
	}
	
	public void init(FilterConfig arg0) throws ServletException {
	}
	
	public void doFilter(ServletRequest args0, ServletResponse args1,
			FilterChain chain) throws IOException, ServletException {
		HttpServletRequest req=(HttpServletRequest)args0;
		
		 //获得所有请求参数名
        Enumeration params = req.getParameterNames();
        String sql = "";
        while (params.hasMoreElements()) {
            //得到参数名
            String name = params.nextElement().toString();
            //System.out.println("name===========================" + name + "--");
            //得到参数对应值
            String[] value = req.getParameterValues(name);
            for (int i = 0; i < value.length; i++) {
                sql = sql + value[i];
            }
        }
        //System.out.println("============================SQL"+sql);
        //有sql关键字，跳转到error.html
        if (sqlValidate(sql)) {
            throw new IOException("您发送请求中的参数中含有非法字符");
            //String ip = req.getRemoteAddr();
        } else {
            chain.doFilter(args0,args1);
        }
    }
	
	//效验
	protected static boolean sqlValidate(String str) {
	    str = str.toLowerCase();//统一转为小写
	    String badStr = "'|and|exec|execute|insert|select|delete|update|count|drop|*|chr|mid|master|truncate|" +
	    		"char|declare|sitename|net user|xp_cmdshell|;|or|-|+|like'|and|exec|execute|insert|create|drop|" +
	    		"table|from|grant|use|group_concat|column_name|" +
	            "information_schema.columns|table_schema|union|where|select|delete|update|order|by|count|*|" +
	            "chr|mid|master|truncate|char|declare|or|;|-|--|+|like|//|/|#|";//过滤掉的sql关键字，可以手动添加 - 少些了 ,
	    String[] badStrs = badStr.split("\\|");
	    for (int i = 0; i < badStrs.length; i++) {
	        if (str.indexOf(badStrs[i]) >= 0) {
	            return true;
	        }
	    }
	    return false;
	}
	
	
}
